Where Did The Misuse Of The Names Gantt And PERT Originate?

PM World JournalVol. II, Issue IV – April 2013Where did Misuse of the names Gantt and PERT originate?Pat Weaverwww.pmworldjournal.netCommentaryWhere did the Misuse of the names Gantt and PERT Originate?By Pat WeaverFollowing on from the publication of my paper Henry L Gantt, 1861 – 1919: Debunking themyths, a retrospective view of his work1 in the December 2012 edition of the PM World Journal,a number of discussions with colleagues has raised the questions: Why are barcharts so often referred to as Gantt Charts? Why are network diagrams (ADM or PDM) so often referred to as PERT charts?My research, outlined in this paper, demonstrates that Gantt’s supposed influence on projectmanagement (outside of his involvement in Taylor’s ‘scientific management’) is an invention ofthe recent past. Looking back at my project management training in the early 1970s, and readingthrough mainframe and mini-computer manuals and early PC system manuals from the 1970sand 80s, the term ‘bar chart’ predominates, and is used uniformly in both UK and USAdocumentation.Similarly, the term PERT was primarily concerned with the calculation of the probability ofcompleting the PERT critical path by a particular date. And by the 1970s PERT was seen to be asuboptimal process for determining this probability, rapidly being replaced by Monte Carlosimulation (for more on PERT and the misuse of the name P1087 PERT.pdf).When the terms PERT and Gantt Chart were used in the 1970s these terms were generally usedto accurately describe the documents and processes the names were originally coined for: GanttCharts for production control tools in factories, PERT for the calculation of probabilities usingstandardised formula.Note: The conclusions in the paragraph above are based on fairly limited resources. I would bevery interested to hear from colleagues if there are examples of the wide spread use of the termsfrom this period – all emails will be responded to.A possible source of the current misuse of the terms.Around 1984/5 Microsoft Project was launched and it used the term ‘Gantt Chart’ for its barchart view and ‘PERT chart’ for its PDM (or CPM) network diagram. Both terms are ‘wrong’form a purist perspective, but the increase in the usage of both terms seems to correlate with therise to dominance of Microsoft Project over many competing PC scheduling tools.This change in usage can be seen using the Google Ngram Viewer. This tool counts the numberof times a word is used in books that have been digitised compared to the total number of words.1Read the December paper: -Featured-Paper.pdf 2013 Patrick Weaverwww.pmworldlibrary.netPage 1 of 5

PM World JournalVol. II, Issue IV – April 2013Where did Misuse of the names Gantt and PERT originate?Pat Weaverwww.pmworldjournal.netCommentaryBy using the Ngram viewer to plot the use of specific words in books we can see an interestingjump in the use of Gantt and Gantt Chart (and PERT Chart) that coincides with the emergingdominance of Microsoft Project as the scheduling tool for the masses.Searching Gantt and Gantt Chart shows a predominance of writing about the man during hiscareer, with the emergence of the term Gantt Chart consistent with the work of Wallace Clarkepublished in 1923. The difference in the level of usage of the term Gantt compared to GanttChart reflects Henry Gantt’s importance in the development of management science. The upturnstarting in the mid 1980s coincides with the release of Microsoft ProjectThe next charts plots the relative use of the terms Bar Chart and Gantt Chart from the emergenceof ‘modern project management’ starting at the end of WW2, through the build up of interest inthe 1980s to the explosion of interest in project management in the 1990s. What this chartdemonstrates is the sudden replacement of the term Bar Chart with Gantt Chart from around1996. 2013 Patrick Weaverwww.pmworldlibrary.netPage 2 of 5

PM World JournalVol. II, Issue IV – April 2013Where did Misuse of the names Gantt and PERT originate?Pat Weaverwww.pmworldjournal.netCommentaryA similar curve can be seen for the term PERT Chart despite PERT being largely obsolete by the1990s.The timing of the upsurge in the use of the terms PERT Chart and Gantt Chart coincides with thelaunch of the Microsoft Windows operating system which was closely followed by theascendency of Microsoft Project as the dominant desk top scheduling tool and the demise ofdozens of other scheduling tools that found the move from DOS to Windows too difficult in ahighly competitive market and simply disappeared.These ramp ups also align with the change in scheduling practice from an environment whereschedulers were seen as skilled practitioners (a hangover from the mainframe days) to a situationwhere scheduling tools were as easy to use as any other Windows application and virtuallyanyone could be a scheduler. Through the 80s and 90s, the software application taught peoplescheduling and the names applied by the tool was accepted without question. With MicrosoftProject having a market share of 90% its names became standard2.Project management was fairly well defined by the end of the 1970s by IPMA, PMI, AIPM and afew other associations, but the new schedulers of the 1990s were largely unaware of the2The effect of the easy-to-use desktop tools on the practice of scheduling is discussed in A Brief Historyof Scheduling at pages 12 -13, see: http://www.mosaicprojects.com.au/Resources Papers 042.html 2013 Patrick Weaverwww.pmworldlibrary.netPage 3 of 5

PM World JournalVol. II, Issue IV – April 2013Where did Misuse of the names Gantt and PERT originate?Pat Weaverwww.pmworldjournal.netCommentaryassociations and their bodies of knowledge. They simply used the names that came out of theirsoftware boxes.SummaryCorrelation is not causation; however, if these preliminary findings hold up to scrutiny, it maybe reasonable to suggest the changing of the name of a bar chart from ‘Bar Chart’ to ‘GanttChart’ and the sudden re-emergence of PERT can both be firmly laid at Microsoft’s door. TheNgram tool has the ability to assist data analysts to push these preliminary findings further –what’s needed is someone with the requisite skills!In the meantime, we should all try to use the correct name for charts, diagrams and processes. Itmay come as a surprise to some, but the name we call things matters because it communicateswhat we are talking about to our audience. The alternative was effectively described by RobertMcCloskey, a US State Department Spokesman several years ago ‘I know that you believe thatyou understood what you think I said, but I am not sure you realise that what you heard is notwhat I meant!’ Effective communication needs a mutual understanding of the terms used, andthis is helped if the terms are consistently used for their correct purpose.I look forward to receiving any comments or feedback particularly relating to the usage of theterms Gantt Chart and PERT Chart in the 1970s and 1980s 2013 Patrick Weaverwww.pmworldlibrary.netPage 4 of 5

PM World JournalVol. II, Issue IV – April 2013Where did Misuse of the names Gantt and PERT originate?Pat Weaverwww.pmworldjournal.netCommentaryAbout the AuthorPatrick WeaverAuthorPatrick Weaver, PMP, PMI-SP, FAICD, FCIOB, is the ManagingDirector of Mosaic Project Services Pty Ltd, an Australian projectmanagement consultancy specialising in project control systems and a PMI RegisteredEducation Provider. Patrick is also the business manager of Stakeholder ManagementPty Ltd. He is a Fellow of the Chartered Institute of Building, Australasia (FCIOB) and aFellow of the Australian Institute of Company Directors (FAICD). He is a member of thePMI College of Scheduling, and the PMI Melbourne Chapter (Australia), as well a fullmember of AIPM, APM (UK) and the College of Performance Management. Patrick hasover 35 years experience in Project Management. His career was initially focused onthe planning and managing of construction, engineering and infrastructure projects inthe UK and Australia. The last 25 years has seen his businesses and experienceexpand to include the successful delivery of project scheduling services and PMOs in arange of government, ICT and business environments; with a strong focus on projectmanagement training. His consultancy work encompasses: developing and advising onproject schedules, developing and presenting PM training courses, managing thedevelopment of internal project control systems for client organisations, and assistingwith dispute resolution and claims management. He is a qualified Arbitrator. In the lastfew years, Patrick has sought to ‘give back’ to the industry he has participated in sinceleaving college through contributions to the development of the project managementprofession. In addition to his committee roles he has presented papers at a wide rangeof project management conferences in the USA, Europe, Asia and Australia, has an ongoing role with the PMOZ conference in Australia and is part of the Australiandelegation to ISO TC258. Patrick can be contacted at patw@mosaicprojects.com.au orat www.mosaicprojects.com.au. 2013 Patrick Weaverwww.pmworldlibrary.netPage 5 of 5

The difference in the level of usage of the term Gantt compared to Gantt Chart reflects Henry Gantt’s importance in the development of management science. The upturn starting in the mid 1980s coincides with the release of Microsoft Project The next charts plots the relative use of the terms Bar Chart and Gantt Chart from the emergence